Table 1:

Neuropathological findings in COVID-19 brain tissue

Viral presence by RT-PCR	53.5% (54/101)
Viral presence by IHC	27.7% (23/83)
Microglial Activation	42.9% (79/184)
Microglial Nodules*	33.3% (14/42)
Lymphoid Inflammation	37.5% (69/184)
Perivascular	33.7% (62/184)
Parenchymal	23.9% (44/184)
Leptomeningeal	23.4% (43/184)
Acute Hypoxic-Ischemic Changes	29.9% (55/184)
Astrogliosis	27.7% (51/184)
Acute/Subacute Brain Infarcts	21.2% (39/184)
Spontaneous Hemorrhage	15.8% (29/184)
Microthrombi	15.2% (28/184)
Alzheimer Type II Astrocytosis	2.7% (5/184)
Neuronophagy	2.2% (4/184)
Neuronal Cell Loss	2.2% (4/184)
Hemorrhagic Transformation of Infarct	2.2% (4/184)
Foci of Demyelination	1.6% (3/184)
Vascular Neutrophilic Plugs	1.6% (3/184)
Perivascular Neutrophils	1.1% (2/184)
Parenchymal Neutrophilic Infiltration	1.1% (2/184)
Leptomeningeal Histiocytes	0.5% (1/184)
Acute Purulent Meningitis	0.5% (1/184)

Table 1: Some histologic findings are likely to be under-reported as reviewed studies are variable in their focus. *Only studies tabulating the prevalence of microglial nodules are included. Studies mentioning microglial nodules in their case series but not enumerating the frequency are excluded.